When body is being pulled from sliding down, frictional force is added or subtracted from the pulling force
When a body is being pulled to prevent it from sliding down an inclined surface, the frictional force opposes the motion. Therefore, the frictional force is added to the pulling force to keep the body in equilibrium and prevent it from sliding down.
To clarify, here are the key points:
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The body tends to slide down the incline due to the force of gravity acting on it.
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To prevent this sliding, an external force must be applied to counteract gravity.
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The external force, which is applied upward along the incline, is the pulling force.
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The frictional force between the body and the incline opposes the direction of the pulling force.
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To keep the body in a state of equilibrium (not accelerating up or down the incline), the pulling force must be greater than or equal to the component of the gravitational force acting downhill. This component is given by (mg * sin(theta)), where (m) is the mass of the body, g) is the acceleration due to gravity, and (theta) is the angle of the incline.
So, in this situation, the frictional force is added to the pulling force to ensure that the net force acting on the body is zero, preventing it from sliding down the incline.